Re: [PATCH net v2 1/3] net: phy: Fix PHY module checks

On 02/07/2017 11:57 PM, maowenan wrote:

quoted

-----Original Message-----
From: Florian Fainelli [mailto:f.fainelli@gmail.com]
Sent: Wednesday, February 08, 2017 3:38 PM
To: netdev@vger.kernel.org
Cc: davem@davemloft.net; andrew@lunn.ch; rmk+kernel@armlinux.org.uk;
maowenan; Florian Fainelli
Subject: [PATCH net v2 1/3] net: phy: Fix PHY module checks

The Generic PHY drivers gets assigned after we checked that the current PHY
driver is NULL, so we need to check a few things before we can safely
derference d->driver. Update phy_attach_direct() and phy_detach() accordingly
to be resilient to these cases.

Even though the Generic PHY driver defaults to phy_probe() which can hardly
fail at the moment, let's fix the label so we don't call phy_detach() on a network
device we have not attached yet.

Fixes: cafe8df8b9bc ("net: phy: Fix lack of reference count on PHY driver")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/phy/phy_device.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index

0d8f4d3847f6..bde240bf8d7b 100644

--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c

@@ -920,7 +920,7 @@ int phy_attach_direct(struct net_device *dev, struct

phy_device *phydev,
 		return -EIO;
 	}

-	if (!try_module_get(d->driver->owner)) {
+	if (d->driver && !try_module_get(d->driver->owner)) {
 		dev_err(&dev->dev, "failed to get the device driver module\n");
 		return -EIO;

Hi Florian,
  Here "return -EIO" will miss decreasing bus->owner reference count.

Good catch thanks!

-- 
Florian